Asbestos is the popular name for several naturally-occurring, chemically-resistant, fibrous forms of impure silicates.
Until relatively recently, asbestos-containing materials were routinely employed as a fireproofing, insulating and/or acoustical material in the construction of all types of buildings ranging from residential homes to office and industrial complexes. Typically, asbestos was combined with other fibrous materials such as fiberglass and a binding agent and then sprayed onto structural units such as steel I-beams and duct-work to a thickness of about 1 to 3 inches.
When studies began to link the presence of airborne asbestos particles with the development of significant respiratory health problems, the use of asbestos as a fireproofing, insulating and acoustical construction material significantly decreased until it was regulatory banned. Long term exposure to airborne asbestos particles has been associated with the development of such serious respiratory diseases as cancer of the lung, pleura, peritoneum and asbestosis. In addition, it is believed that even slight or periodic exposure to relatively low levels of airborne asbestos particles can result in troublesome respiratory problems.
Despite the fact that asbestos-containing materials are no longer employed as a fireproofing, insulating or acoustical construction material, asbestos still poses a significant health risk to millions of people due to its continued presence in those buildings constructed before the use of asbestos-containing materials was discontinued. Although the asbestos in the asbestos-containing material is typically bound by a binding agent to the various structural units within the building, airborne asbestos fibers may still be released as such asbestos containing materials typically become friable over time. To complicate the control of airborne asbestos, asbestos fibers are notorious for their ability to remain airborne for extended periods of time.
Accordingly, it is recognized that in order to properly address the health hazard associated with airborne asbestos, it is necessary not only to cease further use of asbestos-containing material as a fireproofing, insulating or acoustical construction material, but also to control or eliminate that asbestos-containing material already in use.
A temporary, relatively inexpensive method which has been employed to control the airborne release of asbestos fibers is the spraying of either a penetrating or surface-coating encapsulating material onto asbestos-containing materials in an attempt to lock-in the asbestos. However, because of the possibility that such encapsulating coatings will crack or otherwise lose their integrity and once again allow the airborne release of asbestos, this method is not preferred.
The preferred method for controlling the release of airborne asbestos in a structure is to completely remove all asbestos from that structure. This method involves considerable time and expense as it (i) requires a building to be completely sealed off and dismantled so as to expose all structural units coated with an asbestos-containing material, (ii) requires all asbestos-containing material to be debrided from each structural unit under conditions designed to minimize the generation of airborne asbestos particles, and (iii) requires all debrided asbestos-containing material to be collected and disposed of under conditions designed to minimize the generation of airborne asbestos particles. In order to minimize the amount of airborne asbestos particles generated during the removal process, a wetting agent is typically sprayed onto the asbestos-containing material prior to debriding of the material from the structural units.
U.S. Pat. No. 4,699,666, issued to Tidquist et al, discloses a typical wetting agent for use in minimizing the amount of airborne asbestos particles generated during the removal of an asbestos-containing material from a structural unit. The composition disclosed by Weisberg is an aqueous solution of an ethylene oxide homopolymer having a molecular weight of about 100,000 to 5,000,000. While more effective than many other alternatives, the composition of Tidquist et al suffers from several drawbacks, including (i) poor penetration into asbestos-containing materials, (ii) ineffective absorption into the individual asbestos fibers, (iii) inability to effectively prevent the airborne release of asbestos fibers after the composition dries, and (v) creation of a hazardous, slippery condition on the floor of the work area during the removal process.
A composition considered for use in minimizing the number of airborne asbestos particles generated during the removal of an asbestos-containing material from a structural unit, should provide (i) effective penetration into an asbestos-containing matrix, (ii) effective, airborne inhibiting absorption into individual asbestos fibers, (iii) effective, drip preventing initial adhesion to an asbestos-containing material, and (iv) encapsulation of the removed asbestos-containing material so as to prevent the removed asbestos from becoming airborne during collection and disposal.
It is noted that both OSHA and the EPA have created regulatory maximums for the concentration of airborne asbestos fibers which may be generated during the debriding of asbestos-containing materials. Accordingly, any composition intended to be employed in the removal of asbestos-containing materials from a structural unit must be capable of maintaining the concentration of airborne asbestos fibers below the regulatory maximums.